Our pneumatic actuator’s modular design and few components improve field performance. Designed to close upon loss of control pressure (fail-safe), this actuator's nylon-reinforced diaphragm features a large piston area to allow for a low control pressure. The maximum control pressure is 150 psi.
When pneumatic control pressure enters the cylinder during operation, the extended stem travels downward, indicating the valve is open. The adjustable down-stop stops further downward movement, and the gate valve is now fully-open. The actuator is designed to maintain the valve (reverse-acting) in the open position with pneumatic pressure on top of the diaphragm.
Loss of pneumatic pressure allows pressure in the valve body and spring force to move the stem and gate into the closed position.
The extended stem indicates the valve is closed. The metal-to-metal seat between the actuator bonnet and lower stem serves as a secondary seal.
- Decreased maintenance – The rolling diaphragm design eliminates moving o-ring seals, leading to longer seal life.
- Proven reliability – API 6A, PR2 Appendix F-qualified
- Lightweight and quick disconnect – Easy to install and maintain, this unit can be redressed without special tools or external pressure sources.
- Large diaphragm area – Permits use of a low-pressure air or gas control system. A relief valve on the cylinder acts to protect against damage to the diaphragm in case of excessive pressure increases.
- Visual open/close indication – Upper stem extension indicates gate position at a glance.
- Interchangeable with all other AU models, allowing conversion from hydraulic to pneumatic actuation and vice versa